Filter medium



June 17, 1941. H. w, WEBB FILTER MEDIUM Filed Aug. 29, 1936 l 4.1,? 3mm I lfd/Qi,

Gum/aug@ enema@ Julien; 194i This y invention. relates-.1 to; apparatus:` for remo'fv' ing dustffroml air or other'gases; and,K im particuflar, to a illter'inedlumwhicliv consists; of4` arr inter. stitial body.v throug'hz whichr` air mayipass. coated with a liquid. in theail". v

which. catches; and retains thewdust. E

The principal objectv ofuthi'szinve'ntionf'. is toi pro4-`` i vide ai nlter. mediumof thev type described' which will VVoiIer low, uniform andistabl'e: resistance tu:i

the passage of air and yet wilt aiord; suflicient liquid-coated surfaceizo':insure-thatL the airwhich passes through it will'- be thoroughly.v freedc-,from

dust. It is a further object@ ofthsihventllmz to:

wound directly upon arr element oftheairtcleaner in which it is to be incorporatedandinf. thefmethod of winding. e

For a better understanding of' theA nature and" objects of. this invention, reference ismade-to` the following speciilcatiort and the. accompany-v ing drawing wherein the' invention*` isv described: -and illustratedi .Y In the accompanyingl drawingi-A t Figure 1 'is an enlargedi fragmentary perspe tive view of a strand of the flattened: and'` de. formed copper wire from whichisvmade'y the `iil- |ter medium to which-this invention relates; l Figures 2k and 3 are idealized: diagrammatic ;il lustrations of the-winding operationa employed in producing from the *strand1 shown-. im Figure-11. the:

iilter mediumv to which; tliisf inventiorr relates.. Figure 2 illustrates the-operation atwthestart and Figure 3 the operation after'one-winding of each-f` group of strands has been;cornpleted; l

Figure 4 is a. fragmentary view; mainly in vertical section. of anl airrcleaner'iniwhich therezi's have been found particularly suited to-aircleaners` of the type shown in Figurevzd: and for this rea;- son I shall refer to this air. cleanerl wht-.neverin cleaner is .producedindividually andi is preferably thev course` `of the description? of my invention it becomesadvantageous to: refer to. an air' cleaner. IZhe air cleaner IiIl shown. in. Figure 4' is` ofthe oil? bath type. In= it are included' a; body `which consists oiga generally cup-shaped, member Ii andi' aftube- I2: through` which cleaned air is* conducted fromf thezai'rcleaner; The-tube II extends through a central opening: in and is. secured to the bottom-'fof the cup-shaped member and forms therewith an annular. receptacle which is partly filled with: oil before the air cleaner is put. into use;. :Within the upper' end-v of the annular receptacle, thereis disposedv a hollow annularmemv`ber' I^3in which there is enclosed an oil-coated filter mediumga in accordance with this invention. The member I`3- consists of imperforate inner and outer; cylindrical walls I4 and I-5 joined by' outwardly andiupwardly inclined upperand lower v.walls .IBFandL II in*` which there are providedannular, openings I8 andf I9 which are bridged by narrow ,bars. Themember I3 is supported from theupper end of 'thetube I2? and is'of such shape and size that'its l'ower wall is located"u above the level of the oil@v in the-body I I I2f and its: outer .walllis spacedff-rom'andextends upwardly beyondV airr. cleanerIl is` operating, air isdrawn into` the annularvspace between the outer wall of the member' If3 andthe' side wall of the cup-shaped member II, upwardly through the member I3 and out .of the. air cleaner through'` the tubev I2. As: it passes. around the lower outer edgeof the memberl I3, the air depositssome of the dirt which it'carries in' theoil in: the bottom of .the body I'I--jIZ' and picks up some ofv the oil. This oil and the dirt which remains in thev air are carriedv by the air intol-the-member I3 and' deposited on the iilter medium a.

VIn: making. a. lter medium in. accordance with thisginventoml take several strandsj of rather small copper wireand. flattenv and suitably deformr them;- Then I take two groups of these attened and deformedstrands and interwind them around: anarbor, preferably an element ofV the air cleaneriimwhich the filter medium is to be" incorporated, byy moving the twol groups of `strands back and forth in opposite directions c'rosswise of' their direction of travel as they are wound around the arbor. By this procedure,

there is built upon the arbor an interstitial body whose components are maintained in the relative positions in which they are wound by reason of the interwinding and the interengagement of the deformations in the contiguous strands.

After the interstitial body is completed, it is impregnated with a suitable liquid, such as oil, and is then ready for installation in the air cleaner in which it is to be incorporated. The interstitial body will offer little resistance to the passage of air in any direction, will be stable in form and will afford a large surface area which may be coated with liquid. Furthermore. if the pitch or pitches of the turns are properly selected with reference to the widths of the groups of strands employed, the interstitial body will also be of substantiallyuniform intersticity crosswise as well as lengthwise. And it may be added that because the flat surfaces of the strands are inevitably disposed at various angles in the inter- 'of the reel and, thus, reduce the resistance of the filter medium to the passage of air in the direcstltial body, and therefore, serve as deflectors,

the air passing through the interstitial bodywill follow a devious course and, therefore, contact with a greater area of liquid-coated surface and be more thoroughly cleaned than it would if the fiat surfaces were inclined in only one direction.

The copper wire employed in making the filter medium is preferably originally round and 0.007"

to 0.008" in diameter. In the flattening and dea Width 0f 0.022" t0 0.032" and the form illus:

trated in Figure 1. The strand b shown in Figure 1 has in it undulatlons generally parallel to the flat surfaces of the strand, shorter undulations generally at right angles to the flat surfaces of the strand, and also undulations, longer than those first mentioned, at right angles to the fiat surfaces of the strand. The strand hason' its nat surfaces triangular ribs e about 0.001" high, about 0.002" wide at their bases and about 0.0125" apart which extend generally lengthwise of the strand. The ribs e stillen the strands lengthwise and define channels which increase the oil-retaining capacity of the strands. 'I'he stiffness imparted to the strands by the ribs e makes it possible to superpose the larger on the smaller undulations at right angles to the flat surfaces of the strands without obliterating the latter and also lessen the tendency of the strands to straighten out during the winding operation.

vThe winding operation is illustrated diagrammatically in Figures 2 and 3 in which each of the groups'fc and d of strands is representedby a double line. Figure 2 represents the operation at the start and Figure 3 the operation after one winding of reach group of strands has been completed. Figure "3 also illustrates the wind" or structure of the filter medium a. This mode of illustrating the structure of the filter medium has been resorted to because it is impossible by depicting the filter medium-itself to convey a clear conception of its construction. For the sake of clarity, there is represented in Figure 3, only one winding of each group of strands but it will be understood that the lter medium ismany times thicker than the greatest dimension of the strands. b and, consequently, that there are many of these windings superposed one on another in the completed filterV medium.

It lis apparent that the filter medium which is tion of the ,axis of the reel. However, this orientation is, of course, imperfect and, while the flat sides of the strandsV are, on the average, disposed more nearly parallel to the axis of the reel than in any other direction, they are disposed at various angles throughout the filter medium and, consequently.- cause the air to pursue a devious path through it A.and to be ,more thoroughly .cleansed than it would .be if it followed an undeviating course. Since the .,wlnd employed in producing the filter medium is uniform, the resistance to the passage of air-will be uniform throughout the illter medium. And since thev undulations in the juxtaposed turnsof the windings will cause them to interlock and half of each winding-of each group of strands is disposed Y under the half over the corresponding winding of the other group. the structure and, therefore. the'resistance of the nlter medium to .the Passage of air is very stable. i

In making a filter medium for an air cleaner of the type shown in Figure 4, the groups of strands' b are preferably wound directly on the inner-and upper wall assembly Ilof the member'` i3. After the .inner and upper wall assembly is filled, an outer.y and lower wall unit il-I'I which may asthe'drawlngindicates be made in one piecevis assembled with it to enclose the filter medium Ya. Thenl afterV the assembly thus produced has been dipped to coat all of the strands b with oil itis ready for installation in.

the-aircleaner Il.

- nels on its nat surfaces.

3. In anair cleaner, an interstitial illter'rna-` dium which includes groups of flat liquid-wetted strands which are wavy in two non-coplanar directions with ribs which extend lengthwise of .the strands and define liquid-retaining channels on their flat surfaces wound so that leach winding of each group is disposed partly under and partly over the corresponding winding of the other group'. -f Y 4. A body. interstitial in all directions in which there is included a flat metal strand whose flat surfaces are disposed more nearly parallel in one direction than in another.

5. In aninterstitial body, a strand of metal which-is ribbed lengthwise and in which there are impressed generally coplanar undulations of different pitches. f

6. In an air cleaner,va filter medium through which air passes generally in one direction and in which there is included a at metal strand whose flat surfaces are disposed more nearly parallel in the direction of travel of the air than in any other direction.

'1. In an air cleaner, an interstitial filter medium which consists of a liquid-wetted mass of narrow and thin metal ribbon, the ribbon having on its fiat sides minute ribs which extend generally lengthwise of the ribbon and are spaced apart distances several times greater than their transverse dimensions to dene liquid-retaining channels on the fiat sides of the ribbon.

8. In an air cleaner, an interstitial iilter medium through which air passes generally in one direction, the filter medium consisting of a liquid-wetted mass of deformed metal ribbon with the iiat sides of the ribbon disposed at various angles throughout the mass but more nearly parallel in the direction of travel of the air than in any other direction.

9. A tubular interstitial filter body for air cleaners and the like comprising a plurality of helical windings, each winding comprising a layer consisting of contiguous turns, corresponding layers of the two windings being crisscrossed so that a portion of the layer of one winding overlies part of the corresponding layer of the other winding and another portion of the said layer of the rst winding underlies another part of the said corresponding layer of the other winding.

l0. A tubular interstitial iilter body for air cleaners and the like comprising a plurality of helical windings, each winding consisting of a plurality of layers made up of contiguous turns, each layer oi' each winding including a portion overlying part of the corresponding layer of the other winding and a portion underlying another part of the corresponding layer of the other winding,

l1. In an air cleaner, an interstitial filter medium which includes a fiat liquid-wetted strand with ribs which extend lengthwise of the strand and define liquid-retaining channels on its flat surface.

12. In an air cleaner, an interstitial lter medium which includes a fiat liquid-wetted strand of metal in which there are generally coplanar undulations oi' different pitches and which has on its fiat surfaces ribs which extend lengthwise of the strand and denne liquid-retaining channels.

13. In an air cleaner, an interstitial filter medium which includes a nat liquid-wetted strand of metal in which there are generally coplanar undulations of diierent pitches and undulations in another plane vand which has on its ilat surfaces ribs which extend lengthwise of the strand and deiine liquid-retaining channels.

14. A4 tubular interstitial filter body for air,

cleaners and the like comprising a plurality of helical windings of groups of deformed strands, each winding consisting of a plurality of layers made up of contiguous turns, each layer of each winding including a portion overlying part oi' the corresponding layer of the other winding and a portion underlying another part of the corresponding layer of the other winding.

15. In an air cleaner, an interstitial filter medium through which air passes generally in one direction, the filter medium including a fiat strand wound into a body with the ilat sides of the strand disposed at various angles throughout the body but more nearly parallel in the direction of travel of the air than in any other direction.

HARTWELL W. WEBB.

CERTIMGATE oF CORRECTION. Patent No. 2,215,8140. June 17, 19m.

HARTwELL w. WEBB.

It is hereby certified that error appears in the above numbered patent requiring correction as follows: In the drawing, the figure' in the lower right hand corner thereof shouldbe designated as -Fig. 5 page 2, second column, line 5U, for "the" after "under" read -andline 51|., claim 2, strike out "and" before "with; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 18th dey of November, A. D. 19in.

Henry Van Arsdale (Seal) Acting Comissioner of Patents. 

